Predicting the change of course is MUCH more valuable and interesting. If there is a "change in course" then your lines convey nothing about the future, and it is silly to think they convey something about the future.

Then you have to concede that the price could go to $0 or to $1M in the next day. In fact the next second. If you use charts before you buy and sell, you are doing technical analysis.

I like your user name by the way.

Of course the price could go to $0 or $1M in the next second. The chances are slim, but of course this is possible. A chart tells me what the price was in the past I don't know what's so technical about that.

I think it is more likely that the BTC price will go above the green line and then below the red line before April 2014. Does your picture suggest this? No. That is my analysis, do you think it's technical?

But it's not always the whole story. Those who actually want to buy are glad to see a wall anywhere they can find it because it lowers the cost at which their market order for a fixed number of BC gets filled. I don't doubt the idea that the motive behind sell walls is to push sellers to sell at a price more favorable for someone who is trying to buy. I bought a sell wall on Bitfloor (when that sell wall was lower than the last price on Gox, at around $10/coin). Not so large as 2K, but large for Bitfloor. So it doesn't always work out for them if that is indeed the intention behind it. Sell walls help the liquidity of the market. Among other things, they also make possible arbitrage bots, which can force the prices at different exchanges to be the same.